Modeling of Crazing in Rubber-toughened Polymers with LS-DYNA®

Rubber-toughened polymers such as acrylonitrile butadiene styrene (ABS) or high-impact polystyrene (HIPS) are composed of a thermoplastic matrix and small rubber particles, e.g. [1]. The enhanced fracture toughness and ductility, compared to the neat matrix material, are the advantages of rubber-toughened polymers [2]. These macroscopic effects are caused by mechanisms on the micro scale such as shear yielding, void growth and crazing. Crazing is understood as the formation of localized zones of fibrillated material which are able to transfer load. Stress whitening in combination with an increasing volumetric strain clearly indicates the crazing mechanism. The macroscopic volume typically stays constant during shear yielding. The yield and deformation behavior of a rubber-toughened polymer was characterized at the laboratory of DYNAmore GmbH, Stuttgart. For modeling of the dilatant deformation behavior MAT_SAMP-1 was used. Damage modelling depending on the deformation mechanism (shear yielding or crazing) can be taken into account via eGISSMO (i.e. *MAT_ADD_GENERALIZED_DAMAGE).